A sheet metal base panel for use in elevators

ABSTRACT

A sheet metal base panel for use in elevators is disclosed wherein the said base panel is made from sheet metal of low thickness without compromising its structural integrity, by a specialised hemming process. The said base panel is constructed from a single sheet of metal and incorporates the top and bottom header to form a unitary component. The construction is such that the headers can be positioned either way and hence possesses rotational symmetry which enables in easier installation. This is achieved by a special bending of the base panel on all edges of both the top side and bottom side, four times—a first 90° bending (1a) followed by a second 90° bending (1b), a third 90° bending (1c) and a fourth 180° hemming (1d) of the open edge formed after the third 90° bending (1c).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national stage application, filed under 35 U.S.C.§ 371, of International Application No. PCT/IB2022/053949, filed Apr.28, 2022, which claims priority to India Application No. 202141040551,filed Sep. 7, 2021, the contents of both of which as are herebyincorporated by reference in their entirety.

TECHNICAL FIELD

The present invention generally belongs to the field of elevators,specifically to the field of construction of elevator doors and cars andmore specifically relates to the field of sheet metal base panels usedin elevator doors and cars. The present invention relates to a sheetmetal base panel for use in elevators, the said novel feature making thepanels cost effective by reducing the thickness requirement of the sheetmetal without compromising on the structural integrity of the panels.

BACKGROUND

In the elevator industry, base panels made of sheet metals are commonlyused in landing doors, car doors and the car itself.

Conventionally, elevator doors (landing doors and car doors) are made upof the following components—a bottom header, a top header, a base paneland stiffener. The base panels are always made of sheet metal of uniformthickness throughout the panel. The thickness of the sheet metal isdecided based on the strength needed at the weakest point of the panelwhen subjected to mechanical tests as specified by the standards. Thusthe default thickness of the sheet at the weakest point becomes thethickness of the entire panel. Usually, such elevator door or car panelshave base panel thickness of 0.8 mm and above. The elevator cars, alsocalled cabins, are constructed with a steel framework for durability andstrength, and are made up of a ceiling, platform and base panels. Thesides of the elevator cars are also usually made from steel sheet andare trimmed on the inside with paneling. In elevator cars, the basepanels connect the ceiling and the platform.

Therefore, there is extensive use of base panels in the elevatorindustry. However, with rise in sheet metal prices, there is a need toprovide base panels which would reduce the costs involved in manufactureof elevators without compromising on the structural integrity of thebase panels.

DESCRIPTION OF RELATED ART

Chinese Patent Application CN201811591042A discloses an integratedelevator door panel structure wherein the left and right ends of thepanel body are respectively provided with left and right flanges. Theupper and lower ends of the panel are respectively provided with upperand lower flanges. The inner side wall of the hemming is provided withcurling, the inner side of the curling is provided with a connectingpiece, and the bottom of the connecting piece is provided with a guideshoe under the lower hemming; there is an installation cavity, and theinstallation cavity is provided with reinforcing ribs fixed on thesurface of the board. The said patent document claims that such panelstructure has the characteristics of being able to effectively increasethe production efficiency and improve the overall strength of the doorpanel.

Chinese Patent Application CN201620607387U discloses a one-piece bendingtype elevator door which includes a door panel main body, an upper head,a lower head, and a door slider mounted on the said lower head. In themain body of the said elevator door, the sides (left and right sides)are bent in an inverted U-shape to form a package structure. TheU-shaped inverted portion of the door panel body is bent to form theupper head and the lower side is formed in a stepped inversion to formthe lower head, and the stepped portion includes at least one verticalsurface, the said door slider being mounted on the said verticalsurface. The stepped shape described in this example is a secondary stepshape comprising a first stage step connected directly to the door panelbody and a second stage step connected to the first stage step end, thedoor slider being mounted on the vertical plane of the first step. Thepatent document discloses that the said door is made of one-piecemoulding, thereby reducing the door production process and making theprocess simple and easy to achieve and also reduces the cost of theelevator car door.

Chinese Patent Application CN201520720563U discloses an elevator doorwith a new integrated structure, including a main door with a door bodywhich includes a side folding on the left and right sides, an upper anda lower hemming, wherein the lower hem is provided with mounting holesfor mounting a door slide, the said lower hem also folded edge wisethrough a first and second bending edge, and a bending on the third sideand fourth side, thereby forming four stepped off side, wherein thelower end of the vertical flanges of the rim includes a lower hem with avertical mounting plate, wherein the vertical mounting plate is bentthrough the first side and the second side of the bend is bent twice inL-shaped manner, the vertical position corresponding to the lower hem ofthe mounting plate. The mounting hole is located in the verticalmounting plate, wherein the first folded edge and second folded edgebetween the first and three folding edges, grooves are formed forinstallation of slider between the edges of the fourth bend. The saidnovel feature, especially of the lower hem through elevator door plantlower part which adopts the quartic bending, is proposed to not onlyreduce the manufacturing procedure of the door plant, but has alsoguaranteed the rigidity of the door plant and claimed to make theinstallation of the door slider convenient.

Document EP 2008958 A1 discloses a doorway of an elevator that isopened/closed by a door for the elevator. The door for the elevator hasa panel member and a back member provided on a back side of the panelmember. The panel member and the back member are continuous with eachother at each end of a door panel in a width direction thereof. Thepanel member and the back member are continuous with each other in aregion that is formed by bending a board. The back member has aback-side superposition portion superposed on a back surface of thepanel member. Thus, the door panel can be manufactured with ease simplyby bending the board. A strength of the door panel can be ensured aswell through reinforcement resulting from the bending of the board andreinforcement due to the back member. In addition, even in a case where,for example, one hand of a passenger is inserted into a back side of thedoor panel, the passenger can be prevented from having this hand cut bythe door panel.

Document CN 107840229 A discloses a sheet metal base panel according tothe preamble of claim 1.

However, the above said inventions do not completely address theproblems in the prior art, particularly, they do not provide aneffective mechanism to reduce the thickness requirement of the sheetmetal base panels used in elevator landing & car doors and the carsitself, without compromising on the structural integrity of the saidpanels. The patents disclosed in the prior art documents are also notinstallation friendly as the holes to fix the base panel are notsymmetrical. Therefore, there is a need in the art to provide a sheetmetal base panel for use in elevators which is cost friendly as well asinstallation & assembly friendly.

The information disclosed in this background of disclosure section isonly for enhancement of understanding of the general background of theinvention and should not be taken as acknowledgement or any form ofsuggestion that this information forms the prior art already known to aperson skilled in the art.

Further it will be apparent to those skilled in the art that the objectsof this invention have been achieved by providing a sheet metal basepanel for use in elevators, which is unique in nature unlike existingsystems or the ones described in the above prior art in the field knownto the inventors. Various changes may be made in and without departingfrom the concept of the invention. Additional features of the inventionwill be described hereinafter that form the subject of the claims of theinvention. Those skilled in the art should appreciate that they canreadily use the disclosed conception and specific embodiment as a basisfor designing and modifying other methods and structures for carryingout the same purpose of the present invention. Further, features of somestages disclosed in this application may be employed with features ofother stages. Therefore, the scope of the invention is to be determinedby the terminology of the following claims and the legal equivalentsthereof.

BRIEF SUMMARY

One or more problems of the conventional prior art may be overcome byvarious embodiments of the present invention.

It is the primary object of the present invention to provide a sheetmetal base panel for use in elevators which makes the manufacturing ofelevators cost effective when compared to existing sheet metal basepanels.

Another object of the present invention is to provide a sheet metal basepanel for use in elevators wherein the thickness of the said panels isthe lowest possible while at the same time the structural integrity ofthe said panels are not compromised.

Yet another object of the present invention is to provide a sheet metalbase panel for use in elevators wherein the said panels are easy toinstall and assemble.

Still another object of the present invention is to provide a sheetmetal base panel for use in elevators wherein the improved structuredoes not affect the aesthetics of the elevators doors and cars.

Another object of the present invention is to provide a process ofmanufacturing a sheet metal base panel for use in elevators.

These and other objects and advantages of the present subject matterwill be apparent to a person skilled in the art after consideration ofthe following detailed description taken into consideration withaccompanying drawings in which the preferred embodiment of the presentsubject matter are illustrated.

The following disclosure presents a simplified summary of the inventionin order to provide a basic understanding of some aspects of theinvention. This summary is not an extensive overview of the presentinvention. It is not intended to identify the key/critical elements ofthe invention or to delineate the scope of the invention. Its solepurpose is to present some concept of the invention in a simplified formas a prelude to a more detailed description of the invention presentedlater.

The present invention embodies a sheet metal base panel for use inelevators, the said sheet metal base panel comprising of:

-   -   (i) a single main body (1) having top side, bottom side, left        side, and right side, wherein edges of both the top side and        bottom side of the said main body (1) is given a first 90°        bending (1 a) followed by a second 90° bending (1 b) and a        subsequent third 90° bending (1 c) which forms an open edge that        is subsequently hemmed by 180° (1 d) respectively;    -   (ii) at least a pair of holes (1 e, 1 f) symmetric to each        other, on the top side and bottom side respectively of the main        body (1);    -   (iii) at least a pair of stiffeners (2) attached to rear side of        the said main body (1); and,    -   (iv) a bracket (3) and shoe (4) arrangement fixed to the main        body (1) at the said pair of holes (1 f) at one end of the said        main body (1), the said end forming the bottom header.

The present invention further provides a process of manufacturing thesheet metal base panels for use in elevators, the said processcomprising the steps of:

-   -   (i) making a first 90° bending (1 a) using a standard bending        machine, at edges of both the top side and bottom side of the        main body (1) of the said sheet metal base panel;    -   (ii) making a second 90° bending (1 b) following the said first        90° bending (1 a);    -   (iii) making a third 90° bending (1 c) following the said second        90° bending (1 b); and,    -   (iv) making a 180° hemming (1 d) at the open edge formed after        the said third 90° bending (1 c), using the said standard        bending machine; and    -   (v) attaching at least a pair of stiffeners (2) to rear side of        the said main body (1) after 180° hemming at the open edge.

The various advantages of the present invention include:

-   -   1. The base panel becomes at least 50% lighter. Thereby, base        input material cost is reduced.    -   2. Due to the light weight of the door panel, its assembly        becomes easier.    -   3. Door panel is symmetrical in assembly (left, right, top &        bottom) directions.    -   4. All 4-folding edges are welded in the rear side of the base        panel without affecting front side aesthetics.    -   5. Hem sections increase the structural strength of the elevator        door.    -   6. Usually 2 personnel are required to install the door. With        the light weight of the door panel such installation can be        performed by 1 personnel.    -   7. The door constructed using the base panel of improved        structure is 180° symmetric. Therefore, installation is easier        as the headers can be positioned either way.

BRIEF DESCRIPTION OF THE FIGURES

The advantages and features of the present invention will be morereadily apparent by persons skilled in the art when considered inreference to the following description and when taken in conjunctionwith the accompanying drawings listed below.

FIG. 1 is the rear view of an embodiment of the sheet metal base panelfor use in elevators disclosed by the present invention.

FIG. 2 is the sectional view of the sheet metal base panel for use inelevators disclosed by the present invention.

FIG. 3 is the enlarged sectional view (section X-X & Y-Y) of thebendings given to edges of the top side and bottom side of the singlemain body (1) of sheet metal base panel for use in elevators disclosedby the present invention.

FIG. 4A represents the sheet metal base panel before it is administeredthe structure disclosed by the present invention.

FIG. 4B represents the sheet metal base panel after the bendings on allsides as disclosed by the present invention.

FIG. 5A represents the elevator door panel top interface with the liftmechanism, of an embodiment of the sheet metal base panel disclosed bythe present invention, wherein the said base panel is used in theelevator door.

FIG. 5B represents the elevator door panel bottom interface with thesill, of an embodiment of the sheet metal base panel disclosed by thepresent invention, wherein the said base panel is used in the elevatordoor.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

The following description is presented to enable any person skilled inthe art to make and use the invention and is provided in the context ofparticular applications of the invention and their requirements. Thepresent invention can be configured as follows:

Construction

According to a preferred embodiment of the present invention, as shownin FIGS. 1 to 5B, the present invention provides a sheet metal basepanel for use in elevators, the said sheet metal base panel comprisingof:

-   -   (i) a single main body (1) having top side, bottom side, left        side, and right side, wherein edges of both the top side and        bottom side of the said main body (1) are given a first 90°        bending (1 a) followed by a second 90° bending (1 b) and a        subsequent third 90° bending (1 c) which forms an open edge that        is subsequently hemmed by 180° (1 d) respectively;    -   (ii) at least a pair of holes (1 e, 1 f) symmetric to each        other, on the top side and bottom side respectively of the main        body (1);    -   (iii) at least a pair of stiffeners (2) attached to rear side of        the said main body (1); and,    -   (iv) a bracket (3) and shoe (4) arrangement fixed to the main        body (1) at the said pair of holes (1 f) at one end of the said        main body (1), the said end forming the bottom header.

In the preferred embodiment of the present invention, the stiffeners (2)are arranged in the shape of a cross on the rear side of the said mainbody (1), thereby strengthening the mid-section of the base panel.

In another preferred embodiment of the present invention, the thicknessof the stiffeners (2) is more than the thickness of the base panel,contrary to the arrangement in existing elevators.

In an embodiment of the present invention, the sheet metal base paneldisclosed herein is used in the landing door of an elevator.

In another embodiment of the present invention, the sheet metal basepanel disclosed herein is used in the car door of an elevator.

In an embodiment of the present invention wherein the sheet metal basepanel disclosed herein is used in the car door or landing door of anelevator, the said door is of the centre opening type.

In another embodiment of the present invention wherein the sheet metalbase panel disclosed herein is used in the car door or landing door ofan elevator, the said door is of the telescopic opening type.

In yet another embodiment of the present invention, the sheet metal basepanel disclosed herein is used in the cabin/car panel of an elevator.

In an embodiment of the present invention wherein the sheet metal basepanel disclosed herein is used in the landing door of an elevator, asshown in FIG. 5A, the said base panel is installed by fastening the topof the main body (1) to the truck plate (6) through two L-brackets (7)i.e. a fastener riveted along with bracket passing through the pair ofholes (1 e) present on the said base panel. The said truck plate is inturn fastened to the top mechanism of the lift with rollers to move tothe sides when the door opens. In the same embodiment, as shown in FIG.5B, the said base panel is installed by fastening the top of the mainbody (1) to the bracket (3) passing through the pair of holes (1 f) andshoe (4) arrangements are inserted into the sill slot (5) for sliding.

The above mentioned specific embodiments are provided herein forillustrative purposes only. A person skilled in the art would be able toreproduce and/or apply the said construction in various other ways notexpressly mentioned herein, for example, by employing the sheet metalbase panel disclosed herein as cabin/car panels. Such constructions willbe within the spirit and scope of the present patent specification.

Working

It is a well established practice known to any person reasonably skilledin the art that the base panels are always made of sheet metal ofuniform thickness throughout the panel. The thickness of the sheet metalis decided based on the strength needed at the weakest point of thepanel when subjected to mechanical tests as specified by the standards.Thus the default thickness of the sheet at the weakest point becomes thethickness of the entire panel. Usually, elevator door/car panels havebase panel thickness of 0.8 mm and above.

The novel and inventive structure disclosed by the present inventionstrengthens the weakest parts of the panels through a process calledhemming. This allows the weakest parts of the panel to have a higherthickness while the rest of the panel would be having half thethickness. Therefore, this novel and inventive aspect disclosed by thepresent invention allows the use of very thin metal sheets whosethickness range from 0.5 mm to 0.7 mm to manufacture sheet metal basedcomponent for elevators. This unique aspect thus brings a significantreduction in costs while complying with the structural strengthsspecified for the sheet metal components used in elevators.

The two longitudinal sides of the base panel disclosed by the presentinvention act as the top and bottom header and therefore there is norequirement for separately attaching a top and bottom header like inconventional base panels.

The novel feature disclosed by the present invention allows for use ofsheet metal of thickness as low as ≥0.5 mm to ≤0.7 mm in base panel. Theimprovement in the existing structure is due to the use of the 180°hemming process across all the open edges of the sides of the basepanel. Since the edges are the ones that bear the maximum load in thedoor, such hemming arrangement ensures a double wall thickness of crosssectional in the edges although the thickness of the sheet metal is only≥0.5 mm to ≤0.7 mm. Such hemming is found on all four sides of the basepanel. The selective strengthening of the weak points i.e., the edges ofthe base panel, is the reason that a sheet metal of ≥0.5 mm to ≤0.7 mmthickness can be used as input for construction. Since the centre of thedoor panel only has ≥0.5 mm to ≤0.7 mm thickness, stiffeners of 0.8 mmthickness are used to add structural support to the centre to resistdeflection during mechanical tests.

Using the hemming process, it is possible to assimilate the bottom andupper header components into the construction of the base panel tocreate a unit component comprising of three components. The structure ofthe elevator base panel preserves the functionality of the base panel,incorporates the functionality of the upper and bottom header in thesame base panel while increasing the strength by 10%. Conventionally 3different sheets of metal thickness were employed to create the doorpanel—upper and bottom header, base panel, stiffeners. The thickness ofsheet metals used for the headers and the base panels used differvaryingly. The present invention utilizes only one sheet of metal ofonly one thickness to create a unit component that serves as the basepanel, upper header and bottom header.

The present invention achieves the objects set out in the specificationhereinabove by creatively engineering the structure of the elevatorsheet metal base panels used in landing door, car door and the caritself. The uniqueness of the base panel structure disclosed by thepresent invention lies in the following features:

-   -   (i) Reduction in the number of components: A conventional        elevator door comprises of a base panel (thickness ≥0.8 mm)        attached to a top and a bottom header wherein the top and bottom        headers are originally separate components. However, the        structure of the present invention employs a single base panel,        eliminating the two extra components while retaining their        functionality. Same logic is applicable to car panels too        especially those which cater to loads ≤680 kg.    -   (ii) Reduction in the thickness of the sheet metal (base panel        for elevator doors and cars) in the range of ≥0.5 mm to ≤0.7 mm        while maintaining the same structural integrity in order to pass        the mechanical tests as specified in the standards by Bureau of        Indian Standards (BIS) or any other standards local or        international.

Evaluation of Invention and Test Results

A mechanical test was performed on the sheet metal base panels disclosedherein according to IS 14665 (Part 4_Sec 6). The following were thedimensions of the tested samples:

-   -   Thickness of panels: 0.5 mm    -   Stiffener thickness: 0.8 mm    -   Top Frame: 70×40 mm    -   Side Frame: 90×40 mm    -   Clear Opening×Clear Height: Centre opening 2 panel-(700×2000 &        800×2000)

Two samples of the following description were tested:

-   -   Sample 1—Centre opening 2 panel—700×2000 full Steel sheet metal        (0.5 mm)    -   Sample 2—Centre opening 2 panel—800×2000 full Steel sheet metal        (0.5 mm)

According to IS 14665 (Part 4_Sec 6), 345N forces perpendicular to 5 cm2area were applied with a dial gauge with plunger (deformationmeasurement tool).

The test criteria are that there should be no plastic deformation andthe test should not result in the doors being sprung from their guides.

The following test results were obtained:

Location P1 P2 P3 Prototypes Elastic Plastic Elastic Plastic ElasticPlastic Result Sample 1 13.10 0.09 14.61 0.12 14.78 0.10 Passed Sample 212.52 0.03 13.89 0.06 14.13 0.04 Passed

Therefore, the novel and inventive structure disclosed by the presentinvention to improve sheet metal base panels have been shown to pass themechanical requirements of IS 14665 (Part 4_Sec 6).

While there has been shown and described what is considered to bepreferred embodiments of the invention, it will, of course, beunderstood that various modifications and changes in form or detailcould readily be made without departing from the spirit of theinvention. It is therefore intended that the invention be not limited tothe exact forms described and illustrated, but should be constructed tocover all modifications that may fall within the scope of the appendedclaims.

Further embodiments may also be obtained by combining two or moredependent claims.

It will be apparent to those skilled in the art that the objects of thisinvention have been achieved by providing the above invention. Howevervarious changes may be made in the structure of the invention withoutdeparting from the concept of the invention. Therefore, the scope of theinvention is to be determined by the terminology of the following claimsand the legal equivalents thereof

We claim:
 1. A sheet metal base panel for use in elevators, the saidsheet metal base panel comprising of a single main body (1) having topside, bottom side, left side, and right side, wherein edges of both thetop side and bottom side of the said main body (1) are given a first 90°bending (1 a) followed by a second 90° bending (1 b) and a subsequentthird 90° bending (1 c) which forms an open edge that is subsequentlyhemmed in by 180° (1 d) respectively.
 2. The sheet metal base panel foruse in elevators as claimed in claim 1, wherein the sheet metal basepanel contains at least a pair of holes (1 e, 1 f) symmetric to eachother, on the top side and bottom side respectively of the main body(1).
 3. The sheet metal base panel for use in elevators as claimed inclaim 1 or 2, wherein the sheet metal base panel contains at least apair of stiffeners (2) attached to rear side of the said main body (1).4. The sheet metal base panel for use in elevators as claimed in claim2, wherein the sheet metal base panel contains a bracket (3) and shoe(4) arrangement fixed to the main body (1) at the said pair of holes (1f) at one end of the said main body (1), the said end forming the bottomheader.
 5. The sheet metal base panel for use in elevators as claimed inclaim 3, wherein the stiffeners (2) are arranged in the shape of a crosson the rear side of the main body (1), thereby strengthening themid-section of the base panel.
 6. The sheet metal base panel for use inelevators as claimed in claim 3 or 5, wherein the thickness of thestiffeners (2) is more than the thickness of the base panel.
 7. Thesheet metal base panel for use in elevators as claimed in any one of thepreceding claims, wherein the material of the said base panel isstainless steel.
 8. The sheet metal base panel for use in elevators asclaimed in any one of claims 1 to 6, wherein the material of the saidbase panel is mild steel.
 9. The sheet metal base panel for use inelevators as claimed in any one of the preceding claims, wherein thesaid base panel is used in landing doors, car doors and cabin panels ofelevators, said landing door being a centre opening type, or atelescopic opening type.
 10. A process of manufacturing a sheet metalbase panel according to any one of the preceding claims, the saidprocess comprising the steps of: (i) making a first 90° bending (1 a)using a standard bending machine, at edges of both the top side andbottom side of the main body (1) of the said sheet metal base panel;(ii) making a second 90° bending (1 b) following the said first 90°bending (1 a); (iii) making a third 90° bending (1 c) following the saidsecond 90° bending (1 b); and, (iv) making a 180° hemming (1 d) at theopen edge formed after the said third 90° bending (1 c), using the saidstandard bending machine; and (v) attaching at least a pair ofstiffeners (2) to rear side of the said main body (1) after 180° hemmingat the open edge.
 11. An elevator comprising a sheet metal base panelaccording to any one of the claims 1 to 9.